As is known well, a head-separated camera device is configured such that an imaging unit including a solid-state imaging element such as a complementary metal-oxide semiconductor (CMOS) sensor, and a control unit are constituted as separate members. The control unit supplies the solid-state imaging element of the imaging unit with a drive control signal and obtains a video signal by performing a signal processing on an output of the solid-state imaging element. The imaging unit and the control unit are connected through a cable which bundles plural signal lines.
In general, head-separated camera devices are developed for the purpose of, for example, inspecting narrow areas where people cannot enter in. Therefore, imaging elements thereof are demanded to be downsized as much as possible. Further, a cable which is used to connect the imaging unit and the control unit to each other is demanded to be long.
Jpn. Pat. Appln. KOKAI Publication No. 2005-311535 discloses a technique for receiving imaging data without a delay by a control unit in an imaging device comprising a pulse-delay detection unit and a phase-delay detection unit. The pulse-delay detection unit detects a delay amount from a time point when a control unit sends a control signal to a camera head unit to when the control signal returns to the control unit through the camera head unit. The phase-delay detection unit detects a phase difference between a clock signal generated by a timing generator provided in the camera head unit, and an imaging data signal based on a CCD.